Effect of Inferior Vena Cava Filter on Venous Thromboembolism Mortality in Japan　― JROAD and JROAD-DPC Registry Analysis ―

Background: Previous randomized clinical studies have raised concerns about whether inferior vena cava filter (IVCF) can benefit patients with venous thromboembolism (VTE). The present study therefore investigated whether IVCF are associated with in-hospital mortality in Japan. Methods and Results: This study was based on the Diagnosis Procedure Combination database in the Japanese Registry of All Cardiac and Vascular Datasets (JROAD-DPC). Of 2,368,165 patients included in JROAD-DPC, we identified 28,238 who were hospitalized with VTE between 2012 and 2014. We compared in-hospital mortality rates between patients with or without IVCF using propensity score (PS) matching. PS were estimated using logistic regression models in which IVCF was the dependent variable. The other variables consisted of age, sex, Charlson comorbidity index, anti-thrombotic agents and clinical disease status. Patients were aged 68±16 years, and 59.7% were female. Of 28,238 patients, 6,937 (24.5%) were treated with an IVCF. The overall in-hospital mortality was 4.3%. On PS-matched analysis in-hospital mortality was significantly lower with, than without, IVCF (3.1% vs. 4.4%, P<0.001; OR, 0.65; 95% CI: 0.54–0.79). Conclusions: Having an IVCF was independently associated with lower in-hospital mortality in Japanese patients with VTE. This is in sharp contrast to the benefits of IVCF in other countries. The reasons for this difference require further investigation.